Device for the examination of optical properties of surfaces

ABSTRACT

A device for examining the optical properties of surfaces includes at least one first radiation device which emits radiation to a surface to be examined at a first predetermined spatial angle; at least one first detector device for capturing the radiation emitted to and reflected back from the surface, wherein the first detector device, allowing a local resolution of detected radiation, is positioned at least at a second predetermined spatial angle relative to the surface; and at least one further radiation device or second detector device emitting radiation to the surface to be examined at a third predetermined spatial angle or detecting radiation emitted to and reflected back from the surface.

BACKGROUND

The present invention relates to a device for examining the opticalproperties of surfaces. The device will be described below withreference to examining vehicle bodies. However, reference is made to thefact that other kinds of surfaces may also be examined with the deviceof the invention.

Such devices for examining the optical properties of surfaces are knownfrom the prior art. Generally, these use a light source which emitslight to the surface to be examined and a detector that detects andevaluates the light reflected or diffused off said surface. Suchevaluation allows a determination of the optical properties of surfacessuch as color or gloss. Such determination or characterization isrequired since motor-vehicle bodies or their paintwork make differentimpressions on the human eye depending on the incident light, thusrequiring a neutral characterization.

Lately finishes have been gaining popularity which in particularcomprise pigments or so-called flakes. These pigments or flakes are forinstance metal particles statistically distributed in the layer offinish or its surface. More precisely, metal pigments may consist ofvery thin metal flakes acting as miniature reflectors. Standardizingthis type of finishes or measuring the properties of their surfacescreates problems since, depending on the incidence angle of the light,said pigments exhibit different characteristics and for example theslightest variation of the viewing angle may already result in adifferent color or a different brightness. Among other thingsmanufacturers also use finishes having interference pigments which, inparticular in viewing large surface areas, result in color blending atmore or less precisely specified color changing angles (flop) which maylead to largely different color perceptions which in turn leads tovarying overall impressions of the brightness or the color of thefinished surfaces.

These effects and different perceptions of surfaces caused for exampleby different densities, distribution and compositions of finishadditives such as flakes or ornamental pigments cannot be detected withprior art devices since those detectors only supply information on thecomposite intensity of the incident light from various positions on themeasuring surface i.e. they integrate intensity without localresolution.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to include in theexamination of the properties of surfaces a resolution of such changesas caused specifically by shifting views of finished surfaces forexample at slightly different spatial angles.

The device of the present invention for examining the optical propertiesof surfaces comprises at least one first radiation means which emitsradiation to the surface to be examined at a first predetermined spatialsubangle. In addition at least one first detector means is provided forcapturing the radiation emitted to and reflected back from at least aportion of the surface wherein said detector means allows localresolution of the detected radiation and is positioned at a secondpredetermined spatial subangle relative to the surface.

A spatial angle is understood to mean within the scope of the presentinvention, as distinguished from the mathematical concept of a spatialangle, a tuple of spatial subangles. Herein the first component of thespatial angle, i.e. the first spatial subangle α, refers to theprojection angle onto the x/z plane relative to the positive z axis of adirection in space defined by a half straight line beginning in thepoint of origin in a Cartesian coordinate system.

Furthermore, the second component of the spatial angle, i.e. the secondspatial subangle β, refers to the projection angle of said half straightline to the y/z plane relative to the positive z axis. Herein thecoordinate system is oriented such that the measuring surface or atleast portions of the measuring surface lie on the x/y plane.

The spatial angle is thus suitable for clearly characterizing theorientation of the radiation or detector means relative to the surfaceto be examined. The geometrical orientation of the spatial angles willbe illustrated again in the description of the figures. A spatial angleof (0°, 0°) is understood to mean a spatial angle where the radiation ordetector means is positioned above the surface to be examined such thatthe radiation emitting for example from the radiation means is incidenton the surface to be examined substantially perpendicularly.

Further at least one further radiation means or detector means isprovided which emits radiation to the surface to be examined or detectsat least a portion of the radiation emitted to and reflected back fromthe surface.

Preferably said further radiation means emits directional radiation tothe surface to be examined. In another preferred embodiment said furtherradiation means emits diffused radiation.

Radiation means is understood to mean a radiation source or a lightsource, in particular but not exclusively in the shape of light-emittingand/or laser diodes, light bulbs, halogen light bulbs and the like. Aconfiguration of a number of light sources such as a number oflight-emitting diodes having different emission spectra is alsounderstood to mean a radiation means.

A detector means is understood to be any means capable of detecting atleast one parameter of incident light and emitting a signalcorresponding to said parameter. Detector means is intended to includeboth photo sensors, photo cells, photo elements and photo detectors andalso for example cameras, CCD chips and the like.

Preferably the first detector means comprises a preferably planeimage-capturing component which allows a local resolution of detectedradiation. Said plane component may for example be a CCD chip capable ofexamining incident radiation with local resolution and preferably inaddition also color resolution. Said examination with local resolutionallows examining the effects generated by the individual pigments orflakes.

In contrast to this, a plane detector without local resolution would,only by integrating the intensity of radiation incident on eachindividual point on the detector surface across the surface, determinethe composite intensity of the incident radiation and thus would notprovide information on a local origin.

In order to achieve that examination also takes into account effectscaused by differing incident light or incident light at differentspatial angles it is also possible on the one hand to provide a numberof light sources radiating onto the surface at different spatial angles.On the other hand it is also possible to provide instead of a number ofradiation sources, a number of detectors allowing detection at differentspatial angles.

Furthermore it would also be possible to provide a combination, i.e. anumber of radiation means and a number of detector means.

In another preferred embodiment said radiation means and said detectormeans are positioned in one common housing that is substantially opaqueto radiation and comprises an opening through which radiation is guidedonto the surface to be examined. In this way one can assure thatsubstantially only such light enters the individual detectors as isreflected back from the surface to be examined.

In another preferred embodiment at least two radiation means emitradiation on said surface concurrently, at least intermittently.Preferably it is therefore possible that only said first or only saidsecond or both radiation means concurrently emit radiation on saidsurface. If more than two radiation means are provided in anotherembodiment it is conceivable to activate only individual ones or randomcombinations—or all—of said number of radiation means.

In this way different results can be obtained for the surface to beexamined such as information on surface behavior with radiation at onepredetermined angle only, or further data for concurrent radiation at anumber of angles. In this way one can for example achieve anapproximation to diffused daylight or a characterization of gloss.

In another preferred embodiment said second detector means is selectedfrom a group of detector means comprising photo cells, photo elements,photo diodes and the like. As stated above, these elements do not permitlocal resolution of the examined radiation but only an examination ofthe radiation intensity and the spectral characteristics.

The preferred radiation means for resolving the spectral characteristicsis a plurality of LCDs which substantially cover the entire spectrum ofvisible light. In this way a spectral resolution of the receiver meansor detector means is achieved. However, it is also possible to usefrequency-selective elements such as optical gratings in the ray pathafter the surface to be examined.

In another preferred embodiment said first detector means which allowslocal resolution of examined radiation also comprises means fordetermining the total intensity of incident radiation. This can be donein particular but not exclusively through integration of the incidenceintensities on the individual photo cells of a CCD chip.

In another preferred embodiment the first detector means is positionedat a first spatial subangle of substantially 0° above the surface.Preferably said first detector means is also positioned at a secondspatial subangle of 0° above the surface, meaning—as describedabove—that preferably it detects radiation emitting substantiallyperpendicularly from the surface to be examined.

In another preferred embodiment at least one radiation means ispositioned at a first spatial subangle relative to the surface selectedfrom a group of angles including −45°, −15° and +75°. Preferably saidsecond spatial subangle is 0°.

The specified angles are to be understood as approximate values insofaras an angle for example of 45° is understood to include angles within atolerance range of ±5°, i.e. angles between 40° and 50°.

In another preferred embodiment a plurality of radiation means isprovided at predetermined angles. First spatial subangles of −15°, −45°,or +45° and +75° are preferably used. Otherwise it is also possible touse one radiation source and to position the respective detector meansat predetermined first spatial subangles such as in particular but notexclusively −75°, −65°, −45°, −15° or 20°. Any other desired detectionor incidence angles may of course be chosen. However, the magnitudesindicated refer to standards some of which are gauged. Thus far,however, no large first spatial subangles have been used in the priorart, i.e. spatial angles comparatively close to (α=−90°) or (α=+90°).Using such spatial angles allows a better characterization of pigmentsor their distribution on the surface. Preferably at least one detectormeans is positioned at such a first spatial subangle whose amount islarger than (70°, β) and preferably larger than (75°, β).

Preferably said first and said second spatial angles are chosen suchthat a large difference relative to said first spatial subangle willresult, preferably a difference of more than 100°.

In another preferred embodiment at least one detector means ispositioned at a first spatial subangle whose amount is small, preferablyan angle whose amount is smaller than (30°, β) and particularlypreferred smaller or equal (60°, β). Using such small spatial anglesallows a better characterization of pigments having a substantial colorshift.

Preferably said first and said second spatial angle are chosen such thata low difference relative to said first spatial subangle will result,preferably a difference of less than 50°.

In another preferred embodiment at least one radiation means emitsnon-directional or diffused radiation.

Directional radiation is understood to mean such radiation where thelight is incident on the surface to be examined in a substantiallypredetermined direction or at a predetermined spatial angle. In anotherpreferred embodiment at least one radiation means emits directionalradiation (i.e. beams having a defined or sometimes a standardizedaperture, whose rays are substantially parallel).

Non-directional radiation is understood to mean radiation incident onthe surface to be examined at different spatial angles, for exampleafter multiple reflection at the housing surface. This can be achievedin particular but not exclusively by using diffuser or frosted-glassplates.

In another preferred embodiment a number of radiation means aresubstantially positioned on an arc of a circle. In another preferredembodiment it is also conceivable that a number of detector means aresubstantially positioned on an arc of a circle or a number of radiationand detector means are substantially positioned on an arc of a circle.In this way it is achieved that the respective radiation means and/ordetector means are substantially positioned at the same second spatialsubangle or in one plane.

In a preferred embodiment said second spatial subangle at which therespective radiation and detector means are positioned is substantially0°.

In another preferred embodiment at least one spatial subangle at whichthe first detector means is positioned is variable. This is preferablythe first spatial subangle. A preferred embodiment provides that thefirst spatial subangle at which the first detector means is positionedrelative to the surface to be examined, is variable between −90° and90°.

In another preferred embodiment the first spatial subangle at which atleast one radiation means is positioned, is variable. This means thatthe radiation means concerned can emit radiation to the surface fromdifferent directions. This variable spatial angle allows to achieve thatin one measuring method for example light radiates initially at apredetermined spatial angle, then the first spatial subangle at whichthe radiation means is positioned is changed, and then radiation isemitted to the surface to be examined at the changed spatial angle.

Otherwise it is also possible, given a fixed first spatial subangle inthe radiation means, to first position the detector means at a firstspatial subangle and subsequently at a different spatial angle so as toobtain corresponding measuring results. Combinations are alsoconceivable, i.e. variable spatial angles in the radiation means and thedetector means, such as a spatial angle of the detector means variablebetween (0, β) and (+90°, β) and the first spatial subangle of theradiation means variable from (0°, β) to (−90°, β). Preferably thesecond spatial subangle in the above embodiment is substantially 0°.

Another preferred embodiment provides means which allow that both afirst detector means and a second detector means can detect radiation atthe same predetermined spatial angle. These means may for example bebeam splitters which cause a specified portion of the radiation to reachthe first detector means and another portion, the second detector means.It is preferred that said first detector means allows a locallydifferentiating analysis of the radiation and the second detector meansa locally integral intensity examination.

Other means are also conceivable such as partly silvered reflectors,polarizers and the like.

Another preferred embodiment provides a plurality of radiation meanshaving predetermined, substantially regular, angular distances relativeto one another. Said plurality is preferably positioned at the samesecond spatial subangles but at different first spatial subangles. Inthis case the angular distance will result from the difference of saidfirst spatial subangle of a radiation means to that of an adjacentradiation means.

It is furthermore possible that the second spatial subangle is alsovariable, for example it is possible to jointly displace the pluralityof radiation means with reference to the second spatial subangle. Inanother preferred embodiment a plurality of radiation means ispositioned both at different first spatial subangles and differentsecond spatial subangles.

It is likewise conceivable that a plurality of detector means arepositioned at different first and second spatial subangles, and both aplurality of radiation means and a plurality of detector means whichdiffer from one another in respect of their first and second spatialsubangles.

The present invention further relates to a method for examining theoptical properties of surfaces.

One process step provides a first radiation emitted to a surface to beexamined at a first predetermined spatial subangle. Another process stepprovides that the radiation reflected back from the surface to beexamined is detected by means of a first detector means at a secondpredetermined spatial angle wherein said detector means allows localresolution of the detected radiation.

Another process step provides that the radiation reflected back from thesurface to be examined is detected by means of a second detector meansat a third predetermined spatial angle.

Another method according to the invention provides a first process stepwherein a first radiation is directed at a surface to be examined at afirst predetermined spatial subangle.

Another process step provides that a second radiation is directed at thesurface to be examined at a third predetermined spatial angle andanother process step provides that the radiation reflected back from thesurface to be examined is detected by means of a first detector means ata second predetermined spatial angle wherein said detector means allowslocal resolution of the detected radiation.

Preferably the first radiation and the second radiation are emittedconcurrently, at least intermittently.

In another embodiment the first radiation and the second radiation areemitted time-shifted, at least intermittently. Preferably it is possiblewhile measuring to emit radiation to the surface to be examined bothconcurrently and time-shifted since the two procedures serve to obtaindifferent, relevant data on the optical properties of the surface to beexamined.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and embodiments of the device of the presentinvention can be taken from the accompanying drawing. These show in:

FIG. 1 is an embodiment of the present device for examining surfaces;

FIG. 2 is the embodiment of the device of FIG. 1, using anothermeasuring method;

FIG. 3 is a detailed view of the embodiment of the device of FIG. 1;

FIG. 4 is a sectional view of the device of FIG. 1;

FIG. 5 a is an illustration of the measuring result obtained with theembodiment of the device FIG. 1.

FIG. 5 b is an illustration of the measuring result obtained with theembodiment of the device of FIG. 1;

FIG. 5 c is an illustration of the measuring result obtained with theembodiment of the device of FIG. 1;

FIG. 5 d is a representation to illustrate the measuring result.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows an embodiment of a device 1 of the invention for examiningoptical surfaces. It comprises a housing 21 comprising a hollow space 12in its interior. This hollow space is configured as a semicircle or, inthree-dimensional view, as a hemisphere or a hemispherical segment.However, it is also conceivable to provide other structures for saidhollow space. Preferably the inner surface of the hollow space absorbssubstantially all radiation so as to avoid incorrect measuring resultsof directional light due to multiple reflections between the innersurface of the hollow space and the measuring surface. Other preferredembodiments provide a hollow space whose inner surface is configured ofa substantially absorbing layer. In this way it can be achieved thatnon-collimated light is generated under predetermined measuringconditions such that the surface properties under diffused lightconditions can be characterized.

The bottom surface of the housing comprises an opening 8 beneath whichthe surface 3 to be examined is positioned. Reference numeral 15indicates a first radiation means and reference numeral 19, a secondradiation means. Said radiation means 15, 19 emit light to the surface 3to be examined at a predetermined spatial angle. Preferably saidradiation is directional.

The first spatial subangles at which said radiation means 15 and 19 arepositioned, are α=−15° or α=+75°. A spatial subangle α=0° is understoodto mean the angle at which light is directed from the surface 3 to beexamined perpendicularly upwardly in FIG. 1.

In this case the angle β indicating the tilt of the configuration aroundthe axis x is also 0°. The embodiment shown in FIG. 1 provides that allof the radiation directions are positioned on the surface 3 in aperpendicular plane running through the X tubes, i.e. the angle β=0° forall of the radiation directions. Reference numeral 7 indicates a cameraand reference numeral 4, a photo sensor. These two are positioned at anangle α=β=0°, i.e. they detect the light emitting from the surface to beexamined perpendicularly upwardly. The arrangement of camera anddetector ensures that both measuring means detect or characterize thesame light.

It is also conceivable to provide, instead of two radiation means 15 and19, only one radiation means whose spatial angles may be freelyselected. The camera 7 and the photo sensor 4 may be positioned atspatial angles deviating from (0°; 0°) possibly also at differentangles.

The reference numerals 13, 14, 16, 17, and 18 indicate further photodetectors. In this specified embodiment the photo detectors arepositioned at the spatial subangles α=−60° (photo detector 14), α=−30°(photo detector 18), α=20° (photo detector 17), α=30° (photo detector16) and α=60° (photo detector 13). Another photo detector or anotherradiation means may be provided in the opening 20.

Alternatively it is conceivable to provide, in lieu of the detectors,more radiation means or to concurrently provide radiation means anddetectors at the same or adjacent locations. This may for example berealized by means of beam splitters wherein for example dichroicreflectors and the like may be used.

For example a combined radiation and detector means can be configuredsuch that a dichroic reflector positioned at 45° relative to ageometrical connecting line between the radiation means and theincidence point of the radiation on the surface, allows incidence oflight emitting from a radiation means while in respect of reflectingback light reflected back from the surface to be examined it issubstantially light-transmitting, substantially allowing it to passthrough to a detector means.

Reference numerals 11 refer to an adjusting device which preferablyserves to adjust the position of the device for examining surfacesrelative to the surface to be examined. The housing section 22 mayreceive for example displays for the user, the control means of theindividual detector means and radiation means, control means, motors andthe like.

With reference to FIG. 2 the measuring method applied with the device ofthe invention will now be described. The arrows P1 and P2 indicate thelight emitting from the radiation sources 15 and 19 incident on thesurface 3. It radiates along the arrow P4 (illustrated as a dotted line)in the direction of the camera 7. The camera configuration 7 comprises abeam splitter system illustrated in FIGS. 4 to 7. Said beam splittercauses that the ray running along the arrow P4 is split, which ray iscombined of a component originally emitting from the radiation means 6along the arrow P3, and the above-mentioned rays originating from theradiation means 15 and 19.

Since the camera allows local resolution of the illustrated image, alocal resolution of the surface to be examined can thus be displayed. Inthis way the individual pigments or flakes can be rendered visible.

The preferred use of a color camera allows color resolution.

Instead of the system employed herein which comprises both a camera 7and a photo detector 4 it is also conceivable to capture the measurementonly with a camera and to determine the integral intensity, inparticular but not exclusively computer-aided from the image incident inthe camera.

In this way it is possible to examine the details of the surfacetexture, i.e. the precise geometrical position of the pigments, on or inthe individual layers of paint and thus to assess the effects resultingamong other things from the density, distribution and type of theornamental pigments used.

The light emitting from the radiation means 6 is also projected on thesurface 3 where it is captured at different spatial angles. As mentionedabove, the ray reflected back at (0°; 0°) is captured by the detectormeans 4. The illustrated embodiment further provides capturing by meansof the detector means 13, 14, 16, 17 and 18 at the other spatial anglesindicated above.

As mentioned above, the materials to be examined such as the finishesexhibit different optical properties depending on the direction fromwhich they are illuminated. The individual detectors 13 to 18 willtherefore generate different spectral results since they simulatedifferent observation angles for example of a human observer.

Another embodiment provides use of a plurality of radiation meanspositioned at different spatial angles which also simulate differentobservation angles for example by means of a stationary detector. Asmentioned above, the radiation means 19 is positioned at a first spatialsubangle of 75°, i.e. the light emitting from said radiation means isprojected onto the surface 3 to be examined at a comparatively steepangle. This arrangement of the radiation means 19 primarily serves toexamine curved, in particular concave, surfaces.

This application is suitable for detecting pigments having highradiation intensity relative to the environment, as shown in FIG. 5 b.

As mentioned above, the individual radiation means can be operatedindependently of one another. This means that it is possible to emitradiation on the surface only by one of the two radiation means 15 or 19or concurrently by both. Or, the two variants may be combined to carryout a complete measuring cycle.

For examining gloss, this embodiment emits radiation on the surfaceconcurrently with the two radiation means 15 and 19, and the camera 7captures the image.

For examining graininess, the radiation means 15 in the illustratedembodiment is set to −15° for radiating, and detecting takes place at0°.

In addition to the illustrated radiation means, another radiation meansemitting non-directional radiation may be used. In this way one can forexample simulate illumination of the surface 3 on overcast days. Asspecified above, non-directional radiation can be generated inparticular but not exclusively through diffuser disks or individualradiation sources distributed across the space.

It is also conceivable to use directional and non-directional radiationjointly, for example consecutively or substantially concurrently.

FIG. 3 shows a detailed view of the radiation means 19. It comprises ahigh performance LED 41 placed in a housing 43. Furthermore an aperture46 is provided and a lens 44 to direct collimated light at the surface.In addition to one light-emitting diode, a number of light-emittingdiodes may be provided having different emission spectra in particularin visible range. Also, the individual radiation means may compriselight-emitting diodes having different emission spectra. Further,radiation means may be provided emitting substantially white light orlight approximated to white light.

FIG. 4 shows a lateral cross-sectional view of the device of theinvention in FIG. 1. As discussed above, all of the radiation means anddetector means herein are positioned at a spatial subangle β=0°. Thedashed line indicates the spatial subangle β where the device would bepositioned at 45°. A preferred embodiment provides that the device canbe tilted about the point P on the axis x shown in FIG. 1. In this wayit is possible to radiate and to detect light substantially at anydesired spatial subangle β.

As mentioned, the device of the invention comprises a beam splittersystem 2 for directing at the camera the light projected onto thesurface in FIG. 2 along the arrows P1 and P3 and reflected back alongthe arrow P4. It is deflected through a beam splitter 31 substantiallyby 90° and guided through a filter and a lens to the camera 7 or thephotosensitive surface. Another portion (not shown) of the light isguided on to the detector means 4.

Another preferred embodiment provides that the position of the camera 7or the photosensitive surface is displaced relative to the beam S,preferably in the Z and X directions which run vertically in the drawingplane or perpendicularly in the drawing plane, respectively. It isfurther possible to provide at the bottom surface of the housing 39adjusting devices (not shown) to position the device precisely, forexample perpendicularly, relative to the surface to be examined.

The FIGS. 5 a, 5 b and 5 c show examples of the surface effects whichthe device of the invention can capture. FIG. 5 a illustrates a colorshift because of a curved surface. Said color shift can for example beexamined by means of a color picture camera. One can examine in detailwhich changes of the incidence and detection angle lead to which changesin color and brightness. Further embodiments provide to use, not ablack-and-white camera but a color camera which provides additionalinformation on the colors of the individual pigments. Use of ablack-and-white camera and a plurality of radiation sources havingdifferent emission spectra will also provide information on the color ofthe pigments.

It is also apparent that this capturing arrangement allows to capturelight/dark contrasts resulting from different observation angles. Whilethe image appears somewhat darker in the top left area, it is brighterin the lower right area. FIG. 5 d does not show a camera-captured imageof the surface but a schematic illustration of the brightness patternillustrated in FIG. 5 a. Depending on the observation angles, reflectiondiffers largely between the individual pigments and in this way createsthe light/dark transitions illustrated.

FIG. 5 b is a camera-captured measurement of the surface wherein acorresponding spatial angle β (75°, β) of the radiation means causesindividual pigments or flakes to reflect particularly intensely. Suchcapturing allows to examine the distribution of the individual pigmentsor also their sizes and reflective capabilities. For generating thecaptured measurement illustrated in FIG. 5 b it is preferred to use anincidence or first spatial subangle α of a high value. Since the cameradetects beneath 0°, the absolute majority of the light reflected off thesurface does not enter the camera such that the effect of the flakes canbe measured with a minimum of background illumination. The illustrationof FIG. 5 b shows individual pigments.

FIG. 5 c illustrates the structure of the surface to be examined. Inthis way the graininess of the surface can be determined by radiatingdiffused light or at a suitable incidence angle.

It is also possible to obtain the image shown in FIG. 5 c by varying thecamera resolution. Another embodiment provides the use of digitalfilters for this purpose.

1. A device for examining the optical properties of surfaces comprising:at least one first radiation means—emitting radiation at a firstpredetermined spatial angle to a surface to be examined; at least onefirst detector means for capturing the radiation emitted to andreflected back from the surface wherein said first detector meanscomprises an image-capturing component, allowing a local resolution ofdetected radiation, wherein said first detector means is positioned at asecond predetermined spatial angle relative to said surface; at leastone second radiation means which emits radiation to the surface to beexamined, said at least one first and second radiation means beingarranged at different spatial angles relative to the surface to beexamined for emitting radiation onto the surface; and at least onesecond detector means which detects radiation emitted to and reflectedback from the surface to be examined, wherein said second detector meansis arranged at a third predetermined spatial angle and does not permitlocal resolution; wherein said first, second and third spatial anglesare each defined by a tupel of a first spatial subangle and a secondspatial subangle each indicating a projection angle relative to asurface perpendicular to the surface to be examined; and wherein saidtupel of said second spatial angle is (0°, 0°), such that said secondspatial angle is perpendicular above the surface to be examined.
 2. Thedevice according to claim 1, wherein said second radiation means emitsdiffused radiation.
 3. The device according to claim 1 wherein saidsecond radiation means emits directional radiation.
 4. The deviceaccording to claim 1, wherein said first detector means comprises aplane image-capturing component which allows a local resolution ofdetected radiation.
 5. The device according to claim 1, wherein saidfirst detector means comprises a plane image-capturing component whichallows a color resolution of detected radiation.
 6. The device accordingto claim 1, wherein said first detector means is selected from a groupof detector means including cameras and CCD chips.
 7. The deviceaccording to claim 1 wherein said radiation means and said detectormeans are positioned in a common housing that is substantially opaque toradiation and comprises an opening through which radiation is guidedonto the surface to be examined.
 8. The device according to claim 1wherein at least two said radiation means emit radiation on said surfaceconcurrently, at least intermittently.
 9. The device according to claim1 wherein said second detector means is selected from a group ofdetector means including photo cells, photo elements and photo diodes.10. The device according to claim 1 wherein one of said at least onefirst radiation means and said at least one second radiation means ispositioned relative to the surface at said first spatial subangleselected from a group of angles including −45°, −15° and 75°.
 11. Thedevice according to claim 1 wherein one of said at least one firstradiation means and said at least one second radiation means ispositioned relative to the surface at said first spatial subangle whoseamount is larger than 70°.
 12. The device according to claim 1 whereinsaid at least one detector means is positioned relative to the surfaceat said second spatial subangle whose amount is larger than 70°.
 13. Thedevice according to claim 1 including at least two second detector meanseach positioned relative to the surface at said second spatial subangleselected from a group of angles including −75°, −15°, 25°, 45°, 75° and110°.
 14. The device according to claim 1 wherein said at least oneradiation means emits directional radiation.
 15. The device according toclaim 1 wherein said at least one radiation means emits non-directionalradiation.
 16. The device according to claim 1 including a plurality ofradiation means each substantially positioned on an arc of a circle. 17.The device according to claim 1 including a plurality of detector meanseach substantially positioned on an arc of a circle.
 18. The deviceaccording to claim 1 wherein said radiation means and said detectormeans are substantially positioned at the same second spatial subangle.19. The device according to claim 18 wherein said at least one secondspatial subangle at which said first detector means is positioned, isvariable.
 20. The device according to claim 18 wherein saidpredetermined first spatial subangle at which at least one radiationmeans is positioned, is variable.
 21. The device according to claim 18wherein said predetermined second spatial subangle at which at least onedetector means is positioned, is variable.
 22. The device according toclaim 1 wherein said both said radiation means and said detector meansare substantially positioned on an arc of a circle.
 23. The deviceaccording to claim 1 wherein said first detector means and said seconddetector means can detect radiation at the same predetermined spatialangle.
 24. The device according to claim 1 wherein said plurality ofradiation means are provided whose spatial angular distance relative toone another is predetermined and substantially constant.
 25. A methodfor examining the properties of optical surfaces including the steps:directing a first radiation at a surface to be examined at a firstpredetermined spatial subangle; detecting the radiation reflected backfrom the surface to be examined by means of a first detector means at asecond predetermined spatial angle, wherein said detector means allows alocal resolution of detected radiation; and detecting the radiationreflected back from the surface to be examined by means of a seconddetector means at a third predetermined spatial angle, wherein saidsecond detector means does not permit a local resolution; wherein saidsecond and third spatial angles are each defined by a tupel of saidfirst spatial subangle and a second spatial subangle each indicating aprojection angle relative to a surface perpendicular to the surface tobe examined; and wherein said tupel of said second spatial angle is (0°,0°) such that the first detector means is arranged perpendicular abovethe surface to be examined.
 26. A method for examining the properties ofoptical surfaces including the steps: directing a first diffusedradiation at a surface to be examined at a first predetermined spatialsubangle; directing a second directional radiation at a surface to beexamined at a third predetermined spatial angle; and detecting theradiation reflected back from the surface to be examined by means of afirst detector means at a second predetermined spatial angle, whereinsaid detector means allows a local resolution of detected radiation;wherein said second and third spatial angles are each defined by a tupelof a first spatial subangle and a second spatial subangle eachindicating a projection angle relative to a surface perpendicular to thesurface to be examined; and wherein said tupel of said second spatialangle is (0°, 0°) such that the first detector means is arrangedperpendicular above the surface to be examined.
 27. The method accordingto claim 25 further including directing said first radiation and saidsecond radiation occurs concurrently, at least intermittently.
 28. Themethod according to claim 25 further including directing said firstradiation and said second radiation occurs time-shifted, at leastintermittently.